Fungal Melanin Research Articles

Physico-chemical characteristics of melanins culture medium Inocutis dryophila (Berk) Flasson & Niemela

The purpose of the study was to investigate the effect of light treatment on the synthesis of endomelanins from the mycelium of Inocutis dryophila in a liquid culture medium. To identify the effect of light on the synthesis of melanins, the mycelium of Inocutis dryophila was cultivated in a liquid medium in the dark and using blue light treatment. As a result, two types of melanins IDM-1 and IDM-2 were obtained. It has been established that the light factor influences the quantitative release of melanins from the mycelium of Inocutis dryophila into the culture liquid. The use of blue light resulted in lower melanin content in the culture fluid than in the dark. Ultraviolet and infrared spectrometry showed that both types of melanins have typical spectra and graphs for fungal melanins. Infrared spectrometry showed that treatment of mycelium with blue light led to deformation of IDM-1. It was revealed that IDM-2 melanins exhibit greater antiradical activity than IDM-1 melanins. Thus, light treatment of Inocutis dryophila mycelium in a liquid medium affects the quantitative release of melanins into the culture liquid, promotes a change in the structure, as well as manifestation of a biological effect.

The divergence of DHN-derived melanin pathways in Metarhizium robertsii.

The important role of dihydroxynaphthalene-(DHN) melanin in enhancing fungal stress resistance and its importance in fungal development and pathogenicity are well-established. This melanin also aids biocontrol fungi in surviving in the environment and effectively infecting insects. However, the biosynthetic origin of melanin in the biocontrol agents, Metarhizium spp., has remained elusive due to the complexity resulting from the divergence of two DHN-like biosynthetic pathways. Through the heterologous expression of biosynthetic enzymes from these two pathways in baker's yeast Saccharomyces cerevisiae, we have confirmed the presence of DHN biosynthesis in M. roberstii, and discovered a novel naphthopyrone intermediate, 8, that can produce a different type of pigment. These two pigment biosynthetic pathways differ in terms of polyketide intermediate structures and subsequent modification steps. Stress resistance studies using recombinant yeast cells have demonstrated that both DHN and its intermediates confer resistance against UV light prior to polymerization; a similar result was observed for its naphthopyrone counterpart. This study contributes to the understanding of the intricate and diverse biosynthetic mechanisms of fungal melanin and has the potential to enhance the application efficiency of biocontrol fungi such as Metarhizium spp. in agriculture.

Reduction of oxidative rancidification of fungal melanin-coated films in pork lard preservation in trading.

Storage of meat has always been challenging due to its deterioration caused by oxidative rancidity and microbial activity, especially in trading. The melanin-coated film acts as a potent antioxidant, prevents the oxidation of fatty acids, and neutralizes the reactive oxygen species (ROS) helping to withstand or perpetuate the oxidative stress of meat. This study emphasizes the production of fungal melanin extracted from Curvularia lunata and the preparation of two different melanin film combinations of gelatin/melanin and agar/melanin at 0.1% and 0.5% formulation for rancidity stability of coated pork lard. Interpretations revealed the delayed rancidity in both peroxide and acid values with 5.76% in 0.5% agar-coated melanin up to the 11th day which was supported by arithmetical analysis showing p < 0.05 are statistically significant. Further, upon testing the brine shrimp assay for melanin toxicity, 7% were in a mortal state at 1000 µg/mL concentration, considered zero lethality. This result implies that modified coatings, particularly when trading meats, that include fungal melanin can effectively prevent the oxidation of pork lard.

Synthetic fungal melanin UV absorbers

Synthetic fungal melanin UV absorbers

Fungal melanin suppresses airway epithelial chemokine secretion through blockade of calcium fluxing

Respiratory infections caused by the human fungal pathogen Aspergillus fumigatus are a major cause of mortality for immunocompromised patients. Exposure to these pathogens occurs through inhalation, although the role of the respiratory epithelium in disease pathogenesis has not been fully defined. Employing a primary human airway epithelial model, we demonstrate that fungal melanins potently block the post-translational secretion of the chemokines CXCL1 and CXCL8 independent of transcription or the requirement of melanin to be phagocytosed, leading to a significant reduction in neutrophil recruitment to the apical airway both in vitro and in vivo. Aspergillus-derived melanin, a major constituent of the fungal cell wall, dampened airway epithelial chemokine secretion in response to fungi, bacteria, and exogenous cytokines. Furthermore, melanin muted pathogen-mediated calcium fluxing and hindered actin filamentation. Taken together, our results reveal a critical role for melanin interaction with airway epithelium in shaping the host response to fungal and bacterial pathogens.

Characterization and Enhanced Production of Fungal Melanin from Aspergillus Species Isolated from Soil

This study aimed to isolate and identify fungi from soil samples, focusing on their ability to produce melanin. Eleven different genera of fungi were isolated and identified using lactophenol cotton blue staining and microscopic examination, referencing H.L. Barnett and Barry B. Hunter. Among these, only Aspergillus was found to produce melanin. Optimal melanin production conditions were determined to be a 1.5% tyrosine supplement in the growth medium, under shaking conditions (120 rpm) and dark incubation for three weeks, resulting in a yield of 21.08 mg/100 ml. Physiochemical characterization revealed that the extracted melanin was insoluble in organic solvents but soluble in alkaline solutions (NaOH, KOH), and partially soluble in DMSO. Spectrometric analysis using UV-Visible spectroscopy showed characteristic absorption peaks. FTIR indicated functional groups and Scanning Electron Microscopy (SEM) images displayed a granular and heterogeneous surface topology. The study also assessed the effects of different carbon and nitrogen sources, and trace elements on melanin production. Maltose and sucrose were the most effective carbon sources, while peptone was the most effective nitrogen source. Among trace elements, calcium significantly enhanced melanin yield, while copper and zinc had moderate effects. These findings provide valuable insights into optimizing fungal melanin production and its potential industrial applications. The study highlights the sustainable and scalable production of melanin from Aspergillus, contributing to the broader understanding of fungal metabolites and their commercial exploitation. Future research should focus on genetic and metabolic pathways to further enhance melanin biosynthesis and explore its diverse applications.

Characterization of melanin from Exophiala mesophila with the prospect of potential biotechnological applications.

Fungal melanin is an underexplored natural biomaterial of great biotechnological interest in different areas. This study investigated the physical, chemical, electrochemical, and metal-binding properties of melanin extracted from the metallotolerant black fungus Exophiala mesophila strain IRTA-M2-F10. Specific inhibitory studies with tricyclazole and biochemical profiling of whole cells by synchrotron radiation-based Fourier-transform infrared spectral microscopy (SR-FTIRM) were performed. An optimized extraction protocol was implemented, and purified fungal melanin was characterized using an array of spectrophotometric techniques (UV-Vis, FTIR, and EPR) and by cyclic voltammetry (CV) experiments. The metal-binding capacity of melanin extracts was also assessed by using Cr(VI) as a model heavy metal. Inhibitory studies indicated that 1,8-dihydroxynaphthalene may be the main precursor molecule of E. mesophila melanin (DHN-melanin). The biochemical characterization of fungal melanin extracts were benchmarked against those from two melanins comprising the precursor molecule L-3,4-dihydroxiphenylalanine (DOPA-melanin): extracts from the ink of the cephalopod Sepia officinalis and DOPA-melanin synthesized in the laboratory. The CV results of melanin extracts incubated with and without cell suspensions of the electroconductive bacterium Geobacter sulfurreducens were indicative of novel semiquinone/hydroquinone redox transformations specific for each melanin type. These interactions may play an important role in cation exchange for the adsorption of metals and in microbial interspecies electron transfer processes. The obtained results provided further evidence for the DHN-nature of E. mesophila melanin. The FTIR profiling of melanin extracts exposed to Cr(VI), compared to unexposed melanin, resulted in useful information on the distinct surface-binding properties of fungal melanin. The parameters of the Langmuir and Freundlicht isotherms for the adsorption of Cr(VI) were determined and compared to bibliographic data. Altogether, the inherent properties of fungal melanin suggest its promising potential as a biomaterial for environmental applications.

Bioproduction and characterization of melanin pigment produced by the fungal strain Gliocephalotrichum sp. DSGB2

Introduction and Aim: The biosynthetic method of naturally occurring pigment melanin production has become a predominant technique in recent years owing to its cost-effectiveness, low chemical usage, and reduced purification procedure. This study aimed to investigate the significant production, characterization, and biological applications of fungal melanin pigment. Materials and Methods: Melanin production in Gliocephalotrichum sp. DSGB2 strain was carried out by submerged fermentation in tyrosine broth and further purified by acidification and precipitation methods. The purified melanin was characterized by analytical methods such as ultraviolet-visible absorbance, TLC, FTIR spectroscopy, and LC-MS. The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging analysis was performed to evaluate antioxidant properties of melanin. Results: Pigment was confirmed as melanin based on tyrosinase enzyme assay, UV-visible spectroscopy absorbance, TLC, FTIR, and LC-MS analysis. The biosynthesis of melanin was optimized by varying the culture conditions, and the highest yield was obtained under pH 6 at 30ºC. The strain produced about 3.82 gL-1 of melanin in 5 days under optimum conditions and exhibited antioxidant activity. Conclusion: The study provides new ideas into the biosynthesis of water-soluble melanin by the fungal strain Gliocephalotrichum sp. DSGB2 has broad potential applications as an efficient biomaterial in the biopolymer, pharmaceutical sectors, cosmetic, and environmental.

Biosorption of halophilic fungal melanized membrane – PUR/melanin polymer for heavy metal detoxification with electrospinning technology

ABSTRACT Eradication of heavy metal pollution has become the prime priority over the conservation of water resources in the upcoming era. Herein, the study involved the halophilic fungal melanin from Curvularia lunata showed a promising biosorbent for the removal of toxic heavy metals which shows eco-friendly, cost-effective, high stability, and adsorbent efficiency. Polyurethane blended with fungal melanin polymers, makes polymeric nanofibrous membranes through electrospinning techniques. BET isotherms revealed the raw fungal melanin holds a surface area of 3.54 m2/g exhibiting type IV isotherms. BJH results in a total pore volume of 5.79 cc/g with a pore diameter of 6.54 ± 1 nm for pores smaller than 4544.8 Å. Exhibits Eumelanin properties were characterized by FE – SEM and FTIR functional elements. ICPMS confirmed the metal adsorption proficiency on both raw and melanized membranes before and after treatments. Over 17 heavy metals, Ni2+ were adsorbed with 100% efficiency by raw melanin alone with 42.48 µg/L of Ni2+ concentration in the water sample, whereas, Cu2+, Zn2+, Co2+, Cr2+, Pb2+, Mn2+, Al3+, Mo6+, Sb3+, Ba2+, Fe2+, and Mg2+ stands next with 99%. In this study, gentle/simple application of raw fungal melanin (without PUR tailored) can detoxify the maximum concentration of heavy metals present in the water bodies which are further used for irrigation and even drinking purposes. This mycoremediation approach can be easily adapted to industrial production than other high-performance membrane materials with minimal process modification, making it a promising strategy for improving the adsorption properties used in various applications after still furthermore investigation.

Nano-combination for Reviving the Activity of Fluconazole against Rhizopus delemar.

Rhizopus delemar, the main causative pathogen for the lethal mucormycosis and a severe threat during the COVID-19 pandemic, is resistant to most antifungals, including fluconazole, a known selective antifungal drug. On the other hand, antifungals are known to enhance fungal melanin synthesis. Rhizopus melanin plays an important role in fungal pathogenesis and in escaping the human defense mechanism, thus complicating the use of current antifungal drugs and fungal eradication. Because of drug resistance and the slow discovery of effective antifungals, sensitizing the activity of older ones seems a more promising strategy. In this study, a strategy was employed to revive the use and enhance the effectiveness of fluconazole against R. delemar. UOSC-13, a compound synthesized in-house to target the Rhizopus melanin, was combined with fluconazole either as is or after encapsulation in poly (lactic-coglycolic acid) nanoparticles (PLG-NPs). Both combinations were tested for the growth of R. delemar, and the MIC50 values were calculated and compared. The activity of fluconazole was found to be enhanced several folds following the use of both combined treatment and nanoencapsulation. The combination of fluconazole with UOSC-13 caused a 5-fold reduction in the MIC50 value of fluconazole. Furthermore, encapsulating UOSC-13 in PLG-NPs enhanced the activity of fluconazole by an additional 10 folds while providing a wide safety profile. Consistent with previous reports, the encapsulation of fluconazole without sensitization showed no significant difference in activity. Collectively, sensitization of fluconazole represents a promising strategy to revive the use of outdated antifungal drugs back in the market.

Fungal melanins and their potential applications: A Review

Melanins are complex molecules found in many organisms including bacteria, fungi, plants, and animals that have protective functions against stress. In fungi there are several biochemical routes for their synthesis, and their diversity and structural complexity have made their analysis and characterization difficult. However, the possible specific functions of melanins in organisms have been determined. Based on their physicochemical properties, their potential in the application in various areas of interest and benefit of the human being have been visualized, such as in health and medicine, in bioremediation, and in the food industry. In this review, the type of melanins produced by fungi are discussed, as well as their main biological functions, the main biochemical routes involved in their synthesis, and potential applications in various areas. An important research area is visualized to find the best melanin-producing fungi as well as the conditions in which their production is maximized, in order to continue investigating the relationship of the structure of melanin with its biological functions as well as the determination of its physicochemical properties to establish its applications.

The Enigmatic World of Fungal Melanin: A Comprehensive Review.

Synthetic dyes are generally not safe for human health or the environment, leading to the continuous search and growing demand for natural pigments that are considered safer, biodegrade more easily, and are environmentally beneficial. Among micro-organisms, fungi represent an emerging source of pigments due to their many benefits; therefore, they are readily viable on an industrial scale. Among all the bioactive pigments produced by fungi, melanin is an enigmatic, multifunctional pigment that has been studied for more than 150 years. This dark pigment, which is produced via the oxidative polymerization of phenolic compounds, has been investigated for its potential to protect life from all kingdoms, including fungi, from biotic and abiotic stresses. Over time, the research on fungal melanin has attracted a significant amount of scientific interest due to melanin's distinct biological activities and multifarious functionality, which is well-documented in the literature and could possibly be utilized. This review surveys the literature and summarizes the current discourse, presenting an up-to-date account of the research performed on fungal melanin that encompasses its types, the factors influencing its bioactivity, the optimization of fermentation conditions to enhance its sustainable production, its biosynthetic pathways, and its extraction, as well as biochemical characterization techniques and the potential uses of melanin in a wide range of applications in various industries. A massive scope of work remains to circumvent the obstacles to obtaining melanin from fungi and exploring its future prospects in a diverse range of applications.

Highly efficient gene knockout system in the maize pathogen Colletotrichum graminicola using Agrobacterium tumefaciens-mediated transformation (ATMT)

Colletotrichum graminicola, a hemibiotrophic pathogenic fungus, is the causal agent of anthracnose of maize, which causes significant yield losses worldwide, especially in warm and humid maize production regions. An efficient targeted genes knockout protocol is crucial to explore molecular mechanisms of fungal virulence to the host. In this study, we established a gene knockout transformation system by employing Agrobacterium tumefaciens-mediated transformation to knockout genes in M 1.001 strain of C. graminicola. The conidia germination status, induction medium type, and ratio of Agrobacterium cell and conidia suspension were optimized for the knockout of CgBRN1(OR352905), a gene relating to the fungal melanin biosynthesis pathway. Additionally, CgPKS18 (OR352906) and CgCDC25 (OR352903) were knocked out to test the applicability of the gene knockout transformation system. In this established system, transformation efficiency was 176 transformants per 1 × 105 conidia and the homologous recombination efficiency was 53.3 to 75%. Furthermore, disease index, lesion number and lesion size caused by the three above-mentioned mutant strains were found to be reduced significantly compared to the wild-type strain, which indicated reduction in fungal virulence due to the lack of those genes.

Microscopic Raman study of fungal pigment using the genetically amenable rock inhabitant Knufia petricola as a model organism

Fungal pigments such as melanin and carotenoids are distinctive markers of animal and plant pathogenic fungi as well as their environmental relatives. These complex pigments play important roles in pathogenicity and stress tolerance while also being useful as biomarkers. Accordingly, it is important to be able to identify in situ the pigments in black fungi, a group of clinical and environmental importance. In this study, wild-type and genetically modified strains of Knufia petricola A95 and wild fungal cells attached to ancient rock were investigated for their spectroscopic and microscopic Raman features and morphological appearance. Knockout mutants of melanin synthesis genes pks1 (polyketide synthase), sdh1 (scytalone dehydratase), and both pks1 and the carotenoid synthesis gene phd1 (phytoene desaturase) were studied We applied two different Raman microscopes using two lasers, with 633 nm and 488 nm wavelengths. We analyzed and compared Raman spectra between the measured reference substances and the mutant and wild-type strains. In the wild strain WT:A95, the peaks close to melanin peals were found at 1353 cm−1 and 1611 cm−1. There are no characteristic melanin peaks at 1580–1600 cm−1 and around 1350 cm−1 at the spectrum of the Δpks1/Δphd1 mutant and the Δsdh1 mutant. The Δpks1 mutant spectrum has the peaks at the beta-carotene v2 C-C in-plane stretch at 1155 cm−1 and v3 C-CH3 deformation at 1005 cm−1. The peaks of carotenoids and melanin were found in all mutants and the wild strain, except the Δpks1/Δphd1 mutant. Raman spectra allow for discrimination between the various pigments. Hence, interactions between natural fungal melanin, as well as other protective pigments, and complex environmental matrices can be characterized on a range of spatial and temporal scales.

New developments in sunscreens.

Topical sunscreen application is one of the most important photoprotection tool to prevent sun damaging effects in human skin at the short and long term. Although its efficacy and cosmeticity have significantly improved in recent years, a better understanding of the biological and clinical effects of longer wavelength radiation, such as long ultraviolet A (UVA I) and blue light, has driven scientists and companies to search for effective and safe filters and substances to protect against these newly identified forms of radiation. New technologies have sought to imbue sunscreen with novel properties, such as the reduction of calorific radiation. Cutaneous penetration by sunscreens can also be reduced using hydrogels or nanocrystals that envelop the filters, or by binding filters to nanocarriers such as alginate microparticles, cyclodextrins, and methacrylate polymers. Finally, researchers have looked to nature as a source of healthier products, such as plant products (e.g., mycosporines, scytonemin, and various flavonoids) and even fungal and bacterial melanin, which could potentially be used as substitutes or enhancers of current filters.

Aspergillus niger as a cell factory for the production of pyomelanin, a molecule with UV-C radiation shielding activity.

Melanins are complex pigments with various biological functions and potential applications in space exploration and biomedicine due to their radioprotective properties. Aspergillus niger, a fungus known for its high radiation resistance, is widely used in biotechnology and a candidate for melanin production. In this study, we investigated the production of fungal pyomelanin (PyoFun) in A. niger by inducing overproduction of the pigment using L-tyrosine in a recombinant ΔhmgA mutant strain (OS4.3). The PyoFun pigment was characterized using three spectroscopic methods, and its antioxidant properties were assessed using a DPPH-assay. Additionally, we evaluated the protective effect of PyoFun against non-ionizing radiation (monochromatic UV-C) and compared its efficacy to a synthetically produced control pyomelanin (PyoSyn). The results confirmed successful production of PyoFun in A. niger through inducible overproduction. Characterization using spectroscopic methods confirmed the presence of PyoFun, and the DPPH-assay demonstrated its strong antioxidant properties. Moreover, PyoFun exhibited a highly protective effect against radiation-induced stress, surpassing the protection provided by PyoSyn. The findings of this study suggest that PyoFun has significant potential as a biological shield against harmful radiation. Notably, PyoFun is synthesized extracellularly, differing it from other fungal melanins (such as L-DOPA- or DHN-melanin) that require cell lysis for pigment purification. This characteristic makes PyoFun a valuable resource for biotechnology, biomedicine, and the space industry. However, further research is needed to evaluate its protective effect in a dried form and against ionizing radiation.

Extracellular vesicles derived from Talaromyces marneffei contain immunogenic compounds and modulate THP-1 macrophage responses.

Pathogenic eukaryotes including fungi release extracellular vesicles (EVs) which are composed of a variety of bioactive components, including peptides, nucleic acids, polysaccharides, and membrane lipids. EVs contain virulence-associated molecules suggesting a crucial role of these structures in disease pathogenesis. EVs derived from the pathogenic yeast phase of Talaromyces (Penicillium) marneffei, a causative agent of systemic opportunistic mycoses "talaromycosis," were studied for their immunogenic components and immunomodulatory properties. Some important virulence factors in EVs including fungal melanin and yeast phase specific mannoprotein were determined by immunoblotting. Furthermore, fluorescence microscopy revealed that T. marneffei EVs were internalized by THP-1 human macrophages. Co-incubation of T. marneffei EVs with THP-1 human macrophages resulted in increased levels of supernatant interleukin (IL)-1β, IL-6 and IL-10. The expression of THP-1 macrophage surface CD86 was significantly increased after exposed to T. marneffei EVs. These findings support the hypothesis that fungal EVs play an important role in macrophage "classical" M1 polarization. T. marneffei EVs preparations also increased phagocytosis, suggesting that EV components stimulate THP-1 macrophages to produce effective antimicrobial compounds. In addition, T. marneffei EVs stimulated THP-1 macrophages were more effective at killing T. marneffei conidia. These results indicate that T. marneffei EVs can potently modulate macrophage functions, resulting in the activation of these innate immune cells to enhance their antimicrobial activity.

Determination of toxicity and radioprotective properties of bacterial and fungal eumelanin pigments

Purpose Determination of the protective property of melanin, an organic polymer class consisting of phenolic and/or indolic compounds isolated from bacteria and fungi, against fast neutron radiation. To show that these melanin samples, which also have antioxidant and metal chelating properties, can be used as an active ingredient for a drug to be developed against neutrons used in nuclear research and medicine. Materials and methods Bacterial and fungal media were prepared, and melanin pigments were produced and isolated. For molecular characterization of pigments, bacterial genomic DNA extraction, 16S rDNA gene amplification processes, and fungal genomic DNA extraction, ITS1, and ITS4 Gene Regions amplification were performed. The DEL assay was implemented to determine the genotoxicity properties of bacterial and fungal melanin pigments. Samples were prepared in a pad measuring 10 ml volume (60 × 15 mm) at a concentration of 0.2–1 microgram in 1% agarose gel for radiation-absorbed dose measurements. Absorption measurements were made using 241Am-Be fast neutron source and Canberra brand NP series BF3 gaseous detector to determine the neutron radiation absorption capacity of all samples. The results obtained to determine the absorption degrees of melanin samples were compared with paraffin and normal concrete, which are widely used in neutron radiation shielding studies. Results Melanin pigments were obtained using different bacteria and fungi strains. Afterwards, the fast neutron radiation absorption capacity of these purified pigments were determined. Compared to reference samples, these pigments were found to have slightly lower radiation absorbing ability. In addition to these experiments, cytotoxicity tests were carried out using the Yeast DEL assay technique to evaluate the potential for use of these organic pigments in fields such as medicine and pharmacology. According to the results obtained from the tests, it was determined that these melanin samples did not have any toxic effects. Conclusion It was determined that these melanin samples have the potential to be used as a radioprotective drug active substance to protect the tissues and cells of people exposed to neutron radiation after a nuclear accident or nuclear war. Giving a drug that will be developed by using these active ingredients before or after people are exposed to a radiation environment can provide great benefits.

Isolation and Elucidation of Bacterial Melanin's Sun Protection Factor (SPF) for Photoprotection in Cosmetics

The outline of our work delineates the isolation and evaluation of sun screening activity of melanin producers such as Pseudomonas mosselli STGRDS1, Pseudomonas putida STGRDS3, Bacillus amyloliquefaciens STGRDV11, Bacillus subtilis STGRDV5 and Bacillus cereus STGRDT12. All of the isolates were tested against the fungal melanin STGRDM1, which was used as control throughout the study. The Sun Protection Factor (SPF) of formulated creams containing 5% and 10% of melanin was determined with values ranging from 1.96 ± 0.008 to 26.33 ± 0.061; further, the transmission spectroscopy was used to calculate the percentage of protection factor that stipulates the potentiality of pigments showing sunscreen effect.

Sunscreening pigments shape the horizontal distribution of pendent hair lichens in the lower canopy of unmanaged coniferous forests

AbstractHair lichens are distinctive for their capillary growth and typically arboreal occurrence, especially in temperate and boreal forests. They consist of two morphogroups based on cortical pigments: a brown-black group with fungal melanin and a pale yellow-green group with usnic acid. Here we test the hypothesis that these morphogroups are ecologically distinct and thus appropriately regarded as functional groups. We examine their respective horizontal occurrence in the lower canopy of 60-year-old conifer forests on a 250 m tall volcanic cone in south-central British Columbia. Trees on open south-facing slopes and near the summit were found to support mainly melanic hair lichens (Bryoria and Nodobryoria), whereas more densely spaced trees on north-facing slopes and at the base had higher cover values of usnic lichens (especially Alectoria sarmentosa and Ramalina thrausta). The cover of melanic hair lichens was strongly correlated with canopy openness but not for their usnic counterparts. We suggest that investment in light-absorbing melanic pigments is an extreme form of specialization for high light, favouring persistence in dry, sun-exposed canopies of otherwise cool forests. By contrast, the cortex of pendent usnic hair lichens appears to facilitate optimum light transmission to underlying photobionts in shaded sites, though at the cost of sensitivity to light in open habitats, especially in rather dry regions.